Population explosion (Larry, Bozeman, MT, USA)

I recently visited and isolated mountain is central Montana where I have visited from time to time for about 45 years. The mountain, known as Square Butte, rises from the badlands country of less than 4k feet above sea level to an elevation of about 5600 feet. Dry but timbered. Not much for soil.

This time we experienced a presence of ants, mostly the "red ants", that are very common throughout the area, in numbers none of us have ever experienced in all our collective time outdoors in Montana. The nearby ranch owner who has been on the mountain more than probably anyone, has never experienced this phenomenon before either.

There is hardly a yard large space in hundreds of acres at a time which is not crawling with the ants. And extraordinarily large ant hills. The nearby ranch owner who has been on the mountain more than probably anyone, has never experienced this phenomenon before either. 2011 was an epic year for moisture in the area. More rain and snow than a normal 3-5 year period. What do you think might have happened here?

Thanks,
Larry

Hi Larry,

We have contacted James Glasier, antweb's Alberta ants curator, for help with your question and here is what he had to say:

"If the area was timbered, I would probably guess Formica rufa group ants, but he also mentioned badlands, which could indicate Pogonomyrmex, like Dr. James Trager said, so any pictures would make identification easier. The density of ants seems extremely high from his description and I have not seen anything like that. I have had reports of large colonies of Formica podzolica in the last few years that just appear in farmer's yards where they weren't there the year before; colonies three to five meters in diameter compared to regular one meter nests or smaller. I have also had a few people report in southern Alberta an increase in large Formica obscuripes mounds. So it is quite possible these are indications of increased ant populations. I personally haven't collected ants in Montana and don't know the area he refers to, so I can't say for sure what else may be going on... is it possible to get pictures? The other potential thing I could think of is a large nuptial flight occurring right when he was in the area. I know Formica rufa species can be quite aggressive when nuptial flights are going on and run a round quite a bit, and Pogonomyrmex can do that in large numbers as well... so that may also have been what was happening where he was."

Hope this helps,
James Glasier (guest expert), Steffi Kautz & the AntAsk Team